Dr. Judith Joseph is a New York-based psychiatrist, studying happiness. Throughout her life, she's been a high-achiever, graduating from medical school at Columbia and opening her own clinical research institute. She now says she was "pathologically productive" to try to mask feelings of inadequacy. Through her research, and her own experience, Dr. Joseph identified what she refers to as "high-functioning depression". On the outside, she had it all, but she was wrestling with fatigue, poor concentration, and restlessness. In her new book “High Functioning: Overcome Your Hidden Depression and Reclaim Your Joy”, she shares what she's learned with Hoda.